Redeemable Common Stock and Stock Purchase Warrants (Tables)

3 Months Ended

Jul. 31, 2012

Redeemable Common Stock and Stock Purchase Warrant [Abstract]

Schedule Of Share Based Payment Award Stock Warrants Valuation Assumptions [Table Text Block]

Assumptions used to calculate the fair value of these warrants were as follows:

	July 31,			April 30,
	2012			2012
Expected term in years		3.7			3.9
Risk-free interest rates		0.4	%		0.6	%
Volatility		94	%		102	%
Dividend yield		0	%		0